This invention relates to an oropharyngeal airway employed to maintain an unobstructed air passage in an anesthetized, unconscious or sleeping patient by preventing the patient""s tongue from falling backward against the posterior pharyngeal wall and causing the air space to collapse.
Commercial prior art oropharyngeal airway devices are conventionally of single-piece construction, being formed, for example, of relatively rigid plastic material. Such construction is for the purpose of preventing the patient from biting down and collapsing the lumen of the oropharyngeal airway. However, the typical rigid oropharyngeal airway is irritating to the patient who is not totally unconscious or who is not in a deep state of general anesthesia.
Furthermore, there are significant numbers of patients in whom the base of the tongue, and hence the larynx, is caudally positioned in the hypopharynx. This condition is discussed in the following publications: Chou H-C, Wu T-L. Mandibulohyoid distance in difficult laryngoscopy British Journal of Anaesthesia 1993: 71: 335-339; Chou H-C, Wu T-L. Thyromental distancexe2x80x94shouldn""t we redefine its role in the prediction of difficult laryngoscopy (letter). Acta Anaesthesiologica Scandinavica 1998: 42: 136-137; Benumof J L. Prediction of difficult intubation (letter). Acta Anaesthesiologica Scandinavica 1998: 42: 1128; and Chou H-C, Wu T-L. Large hypopharyngeal tongue: a shared anatomic abnormality for difficult mask ventilation, difficult intubation, and obstructive sleep apnea?. Anesthesiology 2001; 94: 936-937. When such condition exists, the commonly available prior art airway devices cannot reach the larynx, the tongue mass cannot be displaced forward and the air passage remains obstructed. Also, the commonly available oropharyngeal airway devices are not easily tolerated in sleeping patients or in patients emerging from general anesthesia when the gag reflex is active while the air passage remains relatively collapsed.
Since the typical commercially available oropharyngeal airway is not made long enough to reach beyond the base of the tongue, as stated above, practitioners often find it necessary to lift the patient""s chin up to raise the base of the tongue from the posterior pharyngeal wall in order to maintain an open air passage. Such maneuver ties up the practitioner""s hands from performing other essential tasks. This is one of the reasons that anesthesia maintained with a face mask and an oropharyngeal airway is becoming less popular even in connection with a brief surgical procedure. In more severe cases, even jaw lifting with both hands and other maneuvers do not compensate for the deficiencies of commonly available oropharyngeal airways, i.e., the patient cannot be ventilated. If the patient""s trachea cannot be intubated immediately, catastrophic results such as hypoxia, brain damage, or even death, can occur.
The adjustable oropharyngeal airway apparatus of the present invention solves the above-described problems. While adjustable airways are known in the prior art they do not incorporate the structural combination and cooperative relationships of the present invention. The following United States patents are considered to be representative of the current state of the prior art in this field: U.S. Pat. No. 3,930,507, issued Jan. 6, 1976, U.S. Pat. No. 5,740,791, issued Apr. 21, 1998, U.S. Pat. No. 4,338,930, issued Jul. 13, 1982, U.S. Pat. No. 4,356,821, issued Nov. 2, 1982, U.S. Pat. No. 4,365,625, issued Dec. 28, 1982, U.S. Pat. No. 5,540,224, issued Jul. 30, 1996, U.S. Pat. No. 4,275,724, issued Jun. 30, 1981, U.S. Pat. No. 3,556,103, issued Jan. 19, 1971, U.S. Pat. No. 5,829,430, issued Nov. 3, 1998, U.S. Pat. No. 5,720,275, issued Feb. 24, 1998, U.S. Pat. No. 5,251,616, issued Oct. 12, 1993, U.S. Pat. No. 4,848,331, issued Jul. 18, 1989, and U.S. Pat. No. 4,211,234, issued Jul. 8, 1980.
As will be seen below, the present invention incorporates a first airway portion in the form of a substantially rigid mouthpiece having an outer mouthpiece surface. The outer mouthpiece surface is engageable by an individual""s teeth and the substantially rigid mouthpiece resists deformation caused by biting of the mouthpiece by the individual.
An elongated, tubular second airway portion formed of flexible, substantially soft, yieldable and resilient material is positioned in an interior passageway defined by the mouthpiece. The second airway portion is maintained under compression by the mouthpiece and the second airway portion can be moved relative to the mouthpiece by the application of external forces thereto. The compressive engagement between the mouthpiece and the second airway portion resists relative movement therebetween so that the second airway portion is maintained in any one of a plurality of selected positions after the external forces are removed.
More particularly, the interior passageway of the mouthpiece includes a central passageway section or area receiving the second airway portion and side passageway sections or areas communicating with the central passageway section and disposed on opposed sides thereof which accommodate bulges formed in the second airway portion caused by compression thereof by the mouthpiece and which also provide for the flow of air through the mouthpiece alongside the second airway portion.
There is no teaching or suggestion of the features noted above in the above-identified prior art patents.
U.S. Pat. No. 5,251,616 is of note since it shows an adjustable tracheostomy tube assembly including a flexible tracheostomy tube which is slidably adjustable relative to a rigid neck collar which is located at a surgical opening formed in the patient""s neck leading to the trachea. A separate three part locking assembly is affixed to the neck collar and, when tightened into place, lockingly engages the tracheostomy tube about the entire outer periphery of the tracheostomy tube to lock it at a desired position.
The structure of the adjustable tracheostomy tube assembly of U.S. Pat. No. 5,251,616 is completely inappropriate for use as an oropharyngeal airway apparatus and the patent fails to provide any hint or suggestion whatsoever that such might be the case.
Adjustment of the second airway portion relative to the mouthpiece of the invention disclosed herein is quickly and readily accomplished. The second airway portion is maintained at a selected position relative to the mouthpiece without having to manipulate a separate locking means as disclosed in U.S. Pat. No. 5,251,616. Furthermore, in the apparatus disclosed and claimed herein air is allowed to pass through the mouthpiece alongside the second airway portion as well as through the second airway portion, a feature not found in U.S. Pat. No. 5,251,616 and one that is highly desirable in an oropharyngeal airway apparatus.
The present invention relates to oropharyngeal airway apparatus for positioning in the mouth of an individual and for retention on the individual as a unit to maintain an unobstructed air passageway in the individual extending from the posterior aspect of the individual""s tongue past the individual""s mouth to the ambient atmosphere.
The adjustable oropharyngeal airway apparatus includes a first airway portion comprising a mouthpiece, the mouthpiece having an outer mouthpiece surface positionable in the mouth of the individual. The mouthpiece includes an inner first airway portion end, an outer first airway portion end, a first airway portion interior passageway extending the length thereof, and openings at the inner and outer first airway portion ends communicating with said first airway portion interior passageway.
The mouthpiece is of unitary, substantially rigid construction for resisting deformation of the mouthpiece when the mouthpiece is placed in the mouth of the individual and the individual""s teeth bite the outer mouthpiece surface. The mouthpiece is of a length insufficient for the inner first airway portion end to reach the posterior aspect of the individual""s tongue where the gag reflex is active when the mouthpiece is positioned in the mouth of the individual.
The first airway portion interior passageway includes a central passageway section and side passageway sections communicating with the central passageway section and disposed on opposed sides thereof.
The apparatus also includes an elongated, double-ended second airway portion substantially longer than the mouthpiece. The second airway portion has a second airway portion interior and openings at opposed ends thereof communicating with the second airway portion interior. One of the opposed ends is a distal end. The second airway portion is positioned in the mouthpiece interior passageway within the central passageway section and is selectively slidably movable relative to the mouthpiece to vary the distance the distal end of the second airway portion is spaced from the inner first airway portion end.
The distal end of the second airway portion is positionable in the individual and projects from the inner first airway portion end, slidable movement of the second airway portion relative to the mouthpiece changing the distance between said distal end and the mouthpiece. The second airway portion is of sufficient length that slidable movement of the second airway portion relative to the mouthpiece enables the distal end to reach or pass the posterior aspect of the individual""s tongue when the second airway portion is slid relative to the mouthpiece to position the distal end a selected distance from said inner first airway portion end.
The second airway portion is tubular and formed of flexible, substantially soft, yieldable, resilient material at its distal end and along the length thereof to lessen the likelihood of gagging reflex in the individual and discomfort to the individual. The second airway portion frictionally engages the mouthpiece at the central passageway section and is maintained under compression by the mouthpiece at all times.
Frictional engagement between the second airway portion and the mouthpiece at the central passageway section and compression of the second airway portion by the mouthpiece at the central passageway section resists relative sliding movement therebetween whereby the length of the second airway portion between the distal end and the inner first airway portion end may be adjusted while in the individual""s mouth by applying manual force to the second airway portion.
The selected adjusted length of the second airway portion between the distal end and the inner first airway portion end is solely maintained by the frictional engagement between the mouthpiece and the second airway portion at the central passageway section and compression of the second airway portion by the mouthpiece in the absence of application of the manual force. The side passageway sections accommodate bulges formed in the second airway portion during compression thereof by the mouthpiece and provide for flow of air through the mouthpiece alongside the second airway portion.
The apparatus further includes means for limiting relative movement between the mouthpiece and the second airway portion to limit the distance between the distal end of the second airway portion and the inner first airway portion end.
Other features, advantages and objects of the present invention will become apparent with reference to the following description and accompanying drawings.